Servo controlled oxygen regulator

ABSTRACT

An oxygen regulator wherein oxygen under pressure passes into a mixing chamber through a first inlet port and a first valve, controlled by a first pressure differential, and ambient air passes into the mixing chamber through a second inlet port and a second valve, controlled by a second pressure differential, to provide breathable fluid capable of maintaining physiological well being in a recipient. The first and second pressure differentials are created by the pressure in the mixing chamber and ambient air pressure. A proportional valve controlled by an aneroid, modifies the effect of the first and second pressure differentials causing the first and second valve to correspondingly open and supply the mixing chamber with correctly ratioed oxygen and ambient air.

United States Patent Cramer et a1.

Jan. 1, 1974 SERVO CONTROLLED OXYGEN REGULATOR lnventors: Robert L.Cramer; John W.

Henneman, both of Davenport, Iowa [73] Assignee: The Bendix Corporation,South Primary Examiner1-1enry T. Klinksiek Assistant ExaminerRichardGerard Attorney-Leo H. McCormick, Jr. et al.

[57] ABSTRACT An oxygen regulator wherein oxygen under pressure passesinto a mixing chamber through a first inlet port and a first valve,controlled by a first pressure differential, and ambient air passes intothe mixing chamber through a second inlet port and a second valve,controlled by a second pressure differential, to provide 137/81 137/91breathable fluid capable of maintaining physiological 58] Fie'ld 'g' R81 l l 4 well being in a recipient. The first and second pressuredifferentials are created by the pressure in the mixing chamber andambient air pressure. A proportional [56] References cued valvecontrolled by an aneroid, modifies the effect of UNITED STATES PATENTSthe first and second pressure differentials causing the 2,608,200 8/l952Stockman 137/81 first and second valve to correspondingly open and 3.4.812 10/ t n... 137/81 supply the mixing chamber with correctly ratioedoxy- 3,509,895 5/1970 Henneman... 137/81 gen and bi i 3,526,241 9/1970Veil 137/81 11 Claims, 2 Drawing Figures 176 I82 1 22a [S 11 I80 250 232/94 172 252 25 78 m 244 240 144 I32 250 I I96 a 241 I 146 L1 2 I28 260 i52 15s 262 n 1 124 wfiw [62 [64 2 M 22 //0 -//& 0 225 220 24-7,, --/22112 1 226 208 oz [91, 92

I 96 2e ,2 22 106 a 94 PATENTED JAN 1 4 SHEET 2 UP 2 1 SERVO CONTROLLEDOXYGEN REGULATOR BACKGROUND OF THE INVENTION In aircraft whereinmaneuvering rapidly changes the altitude of the aircraft, the supply ofoxygen needed to maintain the physiological well being of a recipientcorrespondingly changes. This supply of oxygen is usually controlled bya dilution regulator, such as that disclosed in US. Pat. No. 3,509,895owned by the common assignee of this application and incorporated hereinby reference. These oxygen regulators usually fix the proportion ofoxygen and ambient air flowing to a recipient in relation to theelevation above sea level. In this dilution regulator, a pressure sealresponsive to the pressure of the available oxygen prevents oxygen fromflowing up to a fixed altitude while allowing ambient air to flowunobstructed. Above a predetermined elevation, an aneroid opens anexhaust port to relieve the pressure force on the pressure sealpermitting oxygen to flow while reducing the ambient air flow. At afixed elevation above sea level, the aneroid will completely close theflow of ambient air and provide 100 percent oxygen flow to therecipient. However, the flow of oxygen is strictly proportioned as afunction of the differential pressure between the ambient air and theavailable oxygen. Unfortunately, this type of proportioning does noteffectively supply the minimum amount of oxygen at low altitudes. Theminimum amount of oxygen will maintainthe physiological requirement ofmost recipients flying'an aircraft in a range comparable to sea leveland thereby stabilize the reaction function of the recipient.

SUMMARY OF THE INVENTION We have devised an oxygen regulating apparatusutilizing oxygen controlled servo valves for mixing air and ambient airas a function of altitude to provide a breathable fluid which closelyfollows the minimum physilogical requirements at different altitudes. Inour oxygen regulator, the oxygen under pressure is transmitted through apressure reducing actuation valve which automatically controls andmaintains the oxygen under flow at a uniform pressure to a first mainvalve and a first pilot valve above the first main valve. This sameoxygen flow is further transferred to a double diaphragm wall meanswhich controls the flow of ambient air into a mixing chamber. Thepressure of the breathable fluid in the mixing chamber is communicatedto a first sensing chamber associated with the first pilot valve and asecond sensing chamber associated with a second pilot valve whichcontrols the double diaphragm wall means. A first pressure differentialis created between ambient air and the first sensing chamber foroperating the first pilot valve, simultaneously, a second pressuredifferential is created between ambient air and the second sensingchamber for operating the second pilot valve. Aneroid means responsiveto ambient air is connected to proportioning means for modifying theeffectiveness of the first and second pressure differentials. Thismodification will ratio the available oxygen and ambient air into themixing chamber to provide a breathable fluid capable of maintainingphysiological well being in a recipient. An indicator means associatedwith the first servo valve has a blinker means activated upon oxygenflowing into the mixing chamber to give a visual signal that oxygen flowregulation is taking place.

It is therefore the object of this invention to provide an oxygenregulator having oxygen controlled main valves to mix ambient air andoxygen as a function of altitude for maintaining the physiological wellbeing of a recipient.

It is another object of this invention to provide an oxygen regulatorwith a visual indication of oxygen flow into a mixing chamber.

It is still a further object of this invention to provide an oxygenregulator with a four position actuation control means which reduces thepressure of the available oxygen supply to a predetermined uniformpressure for operating a pair of control servo valves and (I) to selecta mixture of oxygen and ambient air; (2) to select only percent oxygen;(3) to select 100 percent oxygen with safety pressure; and (4) toshut-off the regulator.

It is still a further object of this invention to provide an oxygenregulator having proportioning means responsive to aneroid means forcontrolling the ratio of ambient air and oxygen to meet thephysiological requirements of a recipient.

These and other objects will be apparent from reading this specificationand viewing the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration ofthe oxygen regulator of this invention showing the regulator componentspositioned in response to an aneroid wherein ambient air alone withoutadditional oxygen is sufficient to maintain the physiological well beingof a recipient.

FIG. 2 is a schematic illustration of the oxygen regulator of FIG. 1showing the regulator components positioned in response to the aneroidto provide proportioning of the oxygen and ambient air to meet a changein physiological requirements developed by a change in altitude.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The oxygen regulator 10shown in FIG. 1 consists of a housing 12 having a first inlet port 14connected to a supply of oxygen at a predetermined pressure, a secondinlet port 16 connected to ambient air and an outlet port 18 connectedto the breathing mask (not shown) of a recipient in an aircraft. Anactuator switching means 20, located adjacent the first inlet port 14,reduces the pressure of the available oxygen as it passes into a firstconduit or passageway 22. This oxygen under reduced pressure inpassageway 22 is simultaneously communicated to a first valve means 24,a flow indicator means 26 and diaphragm control means 28 to provide aninstantaneous response allowing the ambient air and oxygen to beproportioned in accordance with the physiological needs of a recipientas determined by aneroid means 30.

The actuation switching means 20 includes a shaft 32 with a helicalgroove 34 on the periphery thereof located in a bore 45 in the housing12. Tactile detents 36, only one shown, representative of OFF-ON, 100percent oxygen and emergency positive pressure positions are located inthe helical groove 34. A large diameter portion 37 of the shaft 32 hasan axial bore 38 while a small diameter portion 40 extends through andis retained in a bearing surface 42 of the housing 12. The shaft 32 hasa slot 44 extending through the small diameter portion 40 adjacent asquare headed end 46. A

spring 48 surrounds the bearing surface in the housing a d holds alocking plate 50 against a keeper 52 which is fixed to the housing byset screw 54. A positioning cap 56 has a square headed end 58 whichengages matching end 46 of shaft 32 as end 60 is positioned against andsecured to locking plate 50 by inserting cross pin 62 through the slot44. The keeper 52 has a series of position locks 64 corresponding to thetactile detents 36 on the shaft 32 which mate with tab 66 on the lockingplate 50.

A pressure reducing piston 68 retained in the bore 45 has a rear stem 70surrounded by a spring 72 retained in axial bore 38 in shaft 32 andfront stem 73 which extend through restricted opening 74 in passageway22. A spring 78 retained by the housing 12 urges a head 76 toward a seat80 surrounding opening 74.

Oxygen under pressure passes through the first inlet port 14 around thehead 76 and against the piston 68 to compress spring 72 and regulate theposition of head 76 with respect to seat 80. When a balance point,representative of a predetermined pressure between the force created byoxygen acting on the piston 68 and the spring 72 is reached, head 76will be positioned on seat 80. This predetermined oxygen pressure inconduit 22 will be communicated simultaneously through a static passage82 into static chamber 84 of the indicator means 26. A diaphragm 86attached to piston 88 separates the static chamber 84 from firstactuation chamber 90. A spherical member 92 with indicia thereon isconnected to the piston 88 through the retention of pin 94 in cam slot96. The first actuation chamber in turn is connected to second actuationchamber 104 of a control chamber 96 associated with the first valvemeans 24. Upon oxygen flowing from the control chamber 96 in response toa demand upon the first valve means 24, a pressure differential will becreated across diaphragm 86 causing piston 88 to move and display avisual indication of the same in window 99 through the indicia onspherical member 92.

The first valve means 24 in the control chamber 96 regulates the flow ofoxygen under pressure available in the passageway 22 from a flow chamber98 into a plurality of flow passages 100 going into a mixing chamber 140through establishment of a pressure differential across a diaphragm 102.The diaphragm 102 separates the control chamber 96 into a flow chamber98 and the second actuation chamber 104. An actuation passage 106connected to passageway 22 has a restriction 108 therein to control thetime required for the oxygen under pressure to equalize in the actuationchamber 104 and the flow chamber 102. Upon equal pressure beingestablished, the pressure in the actuation chamber 104 acting on thelarger surface area of the diaphragm will urge the diaphragm 102 againstseat 110 to prevent flow from the flow chamber 98 into passages 100.

The second actuation chamber 104 is connected to a first pilot valvemeans 112 by an actuation passage 114. The first pilot valve means 112is located in a first sensing chamber 116. The first pilot valve means112 includes a lever arm 118 which is pivotally attached to the housing12 by a pin 120. The lever arm 118 has a face 122 located on one endadjacent the actuation passage 114 and an opening 126 for receivingconnecting pin 124 from a backing plate 128 of a first wall means 130.

The wall means 130 includes a diaphragm 132 which separates the firstsensing chamber 116 from a first ambient chamber 136. The first sensingchamber 116 in turn is connected to the mixing chamber by a firstsensing passage 142. The communication from the mixing chamber 140 ofthe pressure of a breathable fluid contained therein is modified by aproportioning valve means 144 which is responsive to the aneroid means30.

The proportional valve means 144 includes a shaft 146 which extendsthrough and is retained by a bearing wall 148 and a sleeve 150 locatedin bore 152. The sleeve 152 has a shoulder 154 projecting at a rightangle into a manual control means 156. The end of shaft 146 abuts theshoulder to transmit any movement by the aneroid means 30 through thesleeve 150 to modify the pressure signal from the mixing chamber 140.This modification is achieved by the sleeve having a first face 158varying the size of opening 160 from the first sensing passage 142 intothe first sensing chamber 116 and a second face 162 located in a secondsensing passage .164 going to a second sensing chamber 168 of a secondwall means 166.

The second wall means 166 controls the operation through a second valvemeans 170 through a second pressure differential created across adiaphragm 172. The diaphragm I72 separates the second sensing chamber168 from a second ambient chamber 174. Upon the creation of the secondpressure differential, diaphragm 172 will exert a force on lever arm 176of a second pilot valve means 178. The lever arm 176 is pivotallyconnected to the housing 12 by a pin 180 so that upon engagement of end182 with the diaphragm 172, face 184 will uncover oxygen escape passage186 from the diaphragm control means 28.

The diaphragm control means 28 includes a first diaphragm 190 and asecond diaphragm 192 whose outer periphery is retained in the housing 12and whose inner periphery is attached to a piston 188. The firstdiaphragm 190 separates an oxygen control chamber 194 into a firstportion 196 and a second portion 198. The first portion 196 is directlyconnected to the first passageway 22 by a second passageway 200 and tothe second portion through passage 202. A bleed screw 204 located inpassage 202 is adjustable to regulate the communication oxygen underpressure from the first portion 196 to the second portion 198. Thesecond diaphragm 192 separates the first portion 196 of the oxygenchamber from an ambient chamber 206. The piston 188 has a stem 208 whichextends into the ambient chamber 206 and controls the second valve means170.

The second valve means 170 includes a disc 210 which has an axialopening 212 surrounded by a cylindrical guide 214 located on the stem208. A spring 216, which also surrounds the stem 208, is caged betweenthe disc 210 and bottom 218 of the piston 188. The spring 216 will urgedisc 210 against seat 220 to seal the mixing chamber 140 from undesiredambient air communication from chamber 206.

MODE OF OPERATION OF THE PREFERRED EMBODlMENT Upon entering an aircraftas part of the check out procedure, wherein an oxygen supply is carriedfor each individual recipient on the aircraft, an oxygen regulator 10 isactivated. The activation occurs by pushing in on cap 56 to depressspring 48 moving locking tab 66 out of lock 64 and turning the shaft 40,through the engagement of end 46 with square headed end 58, to move theresiliently held spherical ball 222 out of a detent 36 into acorresponding holding detent. As shaft 32 moves, spring 72 will act onpiston 68 to unseat head 76 allowing oxygen under pressure to enter intothe first passageway 22. When the oxygen under pressure in the firstpassageway acting on the face 224 develops a force greater than that ofspring 72, head 76 will again be moved against seat 80 until the oxygenpressure in passageway 22 is reduced.

The oxygen pressure in passageway 22 is simultaneously communicatedthrough passage 82 to static chamber 84, to flow chamber 98 of the firstvalve means 24, and to portion 196 of the oxygen control chamber of thediaphragm control means 28.

Initially, the oxygen under pressure in flow chamber 98 will flow aroundseat 110 into passages 100 until the delayed flow of oxygen throughrestriction 108 into actuation chamber 96 is equal to the pressure ofthe oxygen in the flow chamber 98. With equal pressures in chambers 96and 104 a correspondingly larger force will be created across diaphragm102 in chamber 104 causing the diaphragm to be moved into sealingengagement with seat 110. At the same time, this oxygen pressure will becommunicated through passage 225 into actuation chamber 90. With equalpressure in chambers 84 and 90, spring 226 will move piston 88 to theleft as viewed in FIG. 1, moving the spherical member 92 causing theindicia thereon to indicate a static flow condition.

After the oxygen under pressure in the first portion 196 of the oxygenchamber 194 has passed through restricted passage 202 into the secondportion 198, a pressure differential with ambient chamber 206 will movediaphragm control means 28 toward the ambient air inlet 16.

At ground level, the aneroid means 30 will position the proportioningvalve means 144 in the manner shown in FIG. 1. With 'the outlet 18connected to a breathing mask (not shown), a recipient can inhale thebreathable fluid in the mixing chamber 140. As the breathable fluid isused the pressure of the remaining fluid contained therein iscorrespondingly reduced. This remaining pressure is communicated throughsensing passage 228 into sensing chamber 168. Ambient air pressure isfreely communicated through filter opening 230 into ambient chamber 174.With ambient pressure in chamber 174 and a reduced pressure in chamber168, a pressure differential is created across diaphragm 172. Thispressure differential acts on resiliently positioned stern 232 causinglever arm 176 to pivot on pin 180 and open passage 186. With passage 186opened, the oxygen under pressure in the second portion 198 escapes intothe sensing chamber 168. The oxygen under pressure in the first portion196 and ambient air pressure now combine to move diaphragm valve means188 away from the seat 220 to allow ambient air to enter through theinlet port 16 into the mixing chamber 140.

As the aircraft increases in altitude, the aneroid means 30 will sensethe change in ambient air through sensing ports 234. The change inaltitude will cause the aneroid means 30 to expand causing shaft 146 tomove sleeve 150 to the right as shown in FIG. 2. As the sleeve moves tothe right, the first sensing passage 142 is opened by face-158 movingaway from seat 160 while the second sensing passage 228 is closed bycylindrical cover 240.

At this altitude, upon a recipient inhaling the breathable fluid fromthe mixing chamber 140, the reduced pressure in the mixing chamber 140is proportionally communicated to the first sensing chamber 116 and thesecond sensing chamber 168. With a reduced pressure in chamber 116 andambient pressure in chamber 136, a pressure differential will be createdcausing the lever arm 118 to rotate and allow the oxygen under pressurein the first actuation chamber 104 to escape into the first sensingchamber 116. Now, the oxygen in the flow chamber 98 will move diaphragm102 away from seat 110 allowing the oxygen under pressure in passageway22 to flow through the plurality of passages 100 into the mixing chamber140. With the oxygen flow from the actuation chamber 104, acorresponding reduction in pressure in chamber will also occur. Thepressure of the oxygen in chamber 84 will now move piston 88 causing thespherical member 96 to rotate and display indicia in window 99 to soindicate this.

Simultaneously, as described above at ground level, the diaphragm valvemeans 28 will correspondingly be operated and ambient air will enter themixing chamber 140 through inlet 16. When the combined flow of ambientair and oxygen through passages 100 have raised the pressure of thefluid in the mixing chamber to a predetermined value, this will becommunicated to the first and second sensing chambers 116 and 168,respectively, eliminating the pressure differentials across diaphragms132 and 172. With the pressure differentials eliminated, the resilientlypositioned lever arms 118 and 176, of the pilot valves 112 and 166, willrotate and the faces thereon will seal openings 114 and 186,respectively. With openings 114 and 186 sealed, the oxygen underpressure will again equalize on both sides of diaphragm 102 anddiaphragm piston means 188 to interrupt communication from the flowchamber 98 and ambient chamber 206 into the mixing chamber 140. Theabove cycle is repeated with each inhalation demand, on the mixingchamber 140, only the proportion of ambient air and oxygen admitted tothe mixing chamber will change with an increase in altitude.

At some predetermined altitude, which can be adjusted by turning screw244, the aneroid means 30 will have moved to completely close the secondsensing passage 228 by cover 240, thus only oxygen will be admitted intothe mixing chamber 140. In this position, arm 144 will have moved leverspring arrangement 250 to apply a slight pressure on the diaphragm 132to provide positive pressure breathing. This can also be achieved by theengagement of cam 252 on the manual control 156. The cam will move shaft256 to rotate the lever arm 260 to move the resiliently held tip 262against the diaphragm to aid the ambient air pressure force inestablishing the operational pressure differential across the diaphragm132 upon a depletion of the oxygen in the mixing chamber 140.

We claim:

1. An oxygen regulator for use in an aircraft, comprising:

a housing having a mixing chamber connected to a first inlet portthrough a first passageway, a second inlet port through a secondpassageway, and an outlet port adapted to be connected to a breathingmeans, said first inlet port being connected to a source of oxygen underpressure, said second inlet port being connected to ambient air, saidmixing chamber being adapted to retain a breathable fluid under pressurecapable of maintaining the physiological well being of a recipient;

actuation means adjacent said first inlet port for controlling the flowof said oxygen into said first passageway;

first wall means located in and separating a first chamber in saidhousing into a first sensing chamber and a first ambient chamber, saidfirst sensing chamber being connected to said mixing chamber by a firstsensing passage, said first sensing passage being adapted to carry apressure signal representative of the breathable fluid under pressure insaid mixing chamber to said first sensing chamber, said first wall meansbeing responsive to and moved by a first pressure differential createdbetween said first sensing chamber and said first ambient chamber bysaid pressure signal and ambient air;

first valve means responsive to movement of said first wall means forallowing said oxygen flow to pass from said first passageway into saidmixing chamber;

second wall means located in and separating a second chamber in saidhousing into a second sensing chamber and a second ambient chamber, saidsecond sensing chamber being connected to said mixing chamber by asecond sensing passage, said second sensing passage being adapted tocarry said pressure signal representative of the breathable fluid underpressure in said mixing chamber to said sensing chamber, said secondwall means being responsive to and moved by a second pressuredifferential created between the second sensing chamber and said secondambient chamber by said pressure signal and ambient air;

third wall means located in and separating a third chamber in saidhousing into an oxygen chamber and a third ambient chamber, said oxygenchamber being connected to said first passageway to receive said oxygenunder pressure contained therein, said oxygen chamber being separatedinto a first section and a second section by a restriction, saidrestriction regulating the flow of oxygen under pressure from the firstsection into the second section, said third wall means moving inresponse to a third pressure differential created between the first andsecond sections of the oxygen chamber and said third ambient chamber;

second valve means responsive to movement of said second wall means forcommunicating said second section of the oxygen chamber with said secondsensing chamber to eliminate said third pressure differential;

third valve means connected to said third wall means which is now movedby a fourth pressure differential created between the first section andthe second section and said third ambient chamber and the first section,said third valve means upon moving controlling the flow of ambient airfrom the third ambient chamber into said mixing chamber through saidsecond inlet port; and

control means responsive to changes in altitude for modifying thepressure signal communicated through said first sensing passage and thesecond sensing passage by proportionally restricting the creation ofsaid first and second pressure differencomprising:

blinker means connected to said first passageway for visually indicatingoxygen flow past said first valve means into said mixing chamber.

3. The oxygen regulator, as recited in claim 2,

10 wherein said first valve means includes:

a first diaphragm located in and separating a control chamber into afirst fiow chamber and an actuation chamber, said first flow chamberbeing connected to said first passageway by a centrally located oxygenpassage and to said mixing chamber by a plurality of flow passages, saidactuation chamber being connected to said first sensing chamber by afirst actuation passage, said actuation chamber being connected to saidfirst passageway by a second actuation passage with a restrictionthrough which said oxygen under pressure passes into said first flowchamber;

first pilot valve means having a first lever arm pivotally attached tosaid housing with one end in contact with said first wall means andanother end with a face thereon; and

a first resilient means connected to said first lever arm for urgingsaid face against said housing surrounding said first actuation passagefor preventing oxygen under pressure in the actuation chamber from beingcommunicated into said first sensing chamber, said oxygen under pressurein said actuation chamber moving said diaphragm against a seatsurrounding said oxygen passage to prevent oxygen flow therethrough intosaid flow chamber.

4. The oxygen regulator, as recited in claim 2,

wherein said blinker means includes:

a fourth wall means located in and separating a fourth chamber into astatic pressure chamber and a second flow chamber, said static pressurechamber being connected to said first passageway through a staticpressure to receive the oxygen under pressure therein, said flow chamberbeing connected to said actuation chamber by a third actuation passageto receive the oxygen under pressure contained therein; and

indicator means positioned by movement of said fourth wall meansresponding to a fifth pressure differential between said static chamberand said second flow chamber for visually indicating said fifth pressuredifferential.

5. The oxygen regulator, as recited in claim 4,

wherein said second valve means includes:

a second pilot valve means having a second lever arm pivotally attachedto said housing with one end in contact with said second wall means andanother end with a face thereon; and

a second resilient means connected to said second lever arm for urgingsaid face thereon against the housing surrounding a relief passageconnecting the second section of said oxygen chamber with said secondsensing chamber, said second pressure differential overcoming saidsecond resilient means to allow oxygen under pressure in the secondsection to flow into said second sensing chamber and thereby eliminatesaid third pressure differential.

6. The oxygen regulator, as recited in claim 5,

wherein said third wall means includes:

piston means having a passage therethrough for connecting said firstsection with the second section of said oxygen chamber; and

an adjustable valve associated with said piston means for establishingsaid restriction for regulating the flow of oxygen from the firstsection to the second section.

7. The oxygen regulator, as recited in claim 6,

wherein said third wall means further includes:

a first diaphragm fixed to said housingand secured to said piston meansfor establishing said second section of the oxygen chamber with saidhousing; and

a second diaphragm fixed to said housing and secured to said piston forestablishing said first section in the oxygen chamber, with said firstdiaphragm and said housing.

8. The oxygen regulator, as recited in claim 7,

wherein said piston means inclues:

a stem attached to said piston and extending into said third ambientchamber.

9. The oxygen regulator, as recited in claim 8,

wherein said third valve means includes:

a disc having an axial opening through the center thereof with a face onone side thereon;

a cylindrical guide attached to said disc and adjacent said axialopening, said cylindrical guide surrounding said stem for aligning saiddisc on said piston means;

a cap attached to said stem, said cap engaging said disc causing thedisc to be correspondingly moved as the piston means is moved by saidthird and fourth pressure differentials; and

a spring located between said piston means and said disc for urging saidface toward said second inlet 10 port, said spring allowing saidcylindrical guide to move on said stem to vent said breathable fluidfrom said mixing chamber upon the pressure thereof reaching apredetermined value.

10. The oxygen regulator, as recited in claim 9,

wherein said control means includes:

aneroid means located in a sixth chamber, said sixth chamber being infree communication with ambient air;

shaft having one end connected to said aneroid means and another endextending through a bearing wall of said housing;

sleeve surrounding said shaft having a shoulder abutting said anotherend, said sleeve having a first face thereon which extends into saidfirst passage going to the first sensing chamber and a second facethereon which extends into said second passage going to the secondsensing chamber, said aneroid moving said sleeve through said shaft froma first position where said first face closes said first passage whilesaid second face unobstructs said second passage through a variablenumber of positions corresponding to an increase in altitude to a finalposition where said first face unobstructs said first passage while saidsecond face closes said second passage.

11. The oxygen regulator, as recited in claim 10,

wherein said control means further includes:

a lever arm connected to said shoulder of the sleeve and pivotallyretained in the housing adjacent said first ambient chamber; and

spring means connected to said lever arm and said first diaphragm forproviding a connection with said aneroid means to provide automaticpressure breathing above a predetermined altitude.

1. An oxygen regulator for use in an aircraft, comprising: a housinghaving a mixing chamber connected to a first inlet port through a firstpassageway, a second inlet port through a second passageway, and anoutlet port adapted to be connected to a breathing means, said firstinlet port being connected to a source of oxygen under pressure, saidsecond inlet port being connected to ambient air, said mixing chamberbeing adapted to retain a breathable fluid under pressure capable ofmaintaining the physiological well being of a recipient; actuation meansadjacent said first inlet port for controlling the flow of said oxygeninto said first passageway; first wall means located in and separating afirst chamber in said housing into a first sensing chamber and a firstambient chamber, said first sensing chamber being connected to saidmixing chamber by a first sensing passage, said first sensing passagebeing adapted to carry a pressure signal representative of thebreathable fluid under pressure in said mixing chamber to said firstsensing chamber, said first wall means being responsive to and moved bya first pressure differential created between said first sensing chamberand said first ambient chamber by said pressure signal and ambient air;first valve means responsive to movement of said first wall means forallowing said oxygen flow to pass from said first passageway into saidmixing chamber; second wall means located in and separating a secondchamber in said housing into a second sensing chamber and a secondambient chamber, said second sensing chamber being connected to saidmixing chamber by a second sensing passage, said second sensing passagebeing adapted to carry said pressure signal representative of thebreathable fluid under pressure in said mixing chamber to said sensingchamber, said second wall means being responsive to and moved by asecond pressure differential created between the second sensing chamberand said second ambient chamber by said pressure signal and ambient air;third wall means located in and separating a third chamber in saidhousing into an oxygen chamber and a third ambient chamber, said oxygenchamber being connected to said first passageway to receive said oxygenunder pressure contained therein, said oxygen chamber being separatedinto a first section and a second section by a restriction, saidrestriction regulating the flow of oxygen under pressure from the firstsection into the second section, said third wall means moving inresponse to a third pressure differential created between the first andsecond sections of the oxygen chamber and said third ambient chamber;second valve means responsive to movement of said second wall means forcommunicating said second section of the oxygen chamber with said secondsensing chamber to eliminate said third pressure differential; thirdvalve means connected to said third wall means which iS now moved by afourth pressure differential created between the first section and thesecond section and said third ambient chamber and the first section,said third valve means upon moving controlling the flow of ambient airfrom the third ambient chamber into said mixing chamber through saidsecond inlet port; and control means responsive to changes in altitudefor modifying the pressure signal communicated through said firstsensing passage and the second sensing passage by proportionallyrestricting the creation of said first and second pressure differentialrespectively to allow ambient air and oxygen under pressure into saidmixing chamber which satisfies the physiological needs of saidrecipient.
 2. The oxygen regulator, as recited in claim 1, furthercomprising: blinker means connected to said first passageway forvisually indicating oxygen flow past said first valve means into saidmixing chamber.
 3. The oxygen regulator, as recited in claim 2, whereinsaid first valve means includes: a first diaphragm located in andseparating a control chamber into a first flow chamber and an actuationchamber, said first flow chamber being connected to said firstpassageway by a centrally located oxygen passage and to said mixingchamber by a plurality of flow passages, said actuation chamber beingconnected to said first sensing chamber by a first actuation passage,said actuation chamber being connected to said first passageway by asecond actuation passage with a restriction through which said oxygenunder pressure passes into said first flow chamber; first pilot valvemeans having a first lever arm pivotally attached to said housing withone end in contact with said first wall means and another end with aface thereon; and a first resilient means connected to said first leverarm for urging said face against said housing surrounding said firstactuation passage for preventing oxygen under pressure in the actuationchamber from being communicated into said first sensing chamber, saidoxygen under pressure in said actuation chamber moving said diaphragmagainst a seat surrounding said oxygen passage to prevent oxygen flowtherethrough into said flow chamber.
 4. The oxygen regulator, as recitedin claim 2, wherein said blinker means includes: a fourth wall meanslocated in and separating a fourth chamber into a static pressurechamber and a second flow chamber, said static pressure chamber beingconnected to said first passageway through a static pressure to receivethe oxygen under pressure therein, said flow chamber being connected tosaid actuation chamber by a third actuation passage to receive theoxygen under pressure contained therein; and indicator means positionedby movement of said fourth wall means responding to a fifth pressuredifferential between said static chamber and said second flow chamberfor visually indicating said fifth pressure differential.
 5. The oxygenregulator, as recited in claim 4, wherein said second valve meansincludes: a second pilot valve means having a second lever arm pivotallyattached to said housing with one end in contact with said second wallmeans and another end with a face thereon; and a second resilient meansconnected to said second lever arm for urging said face thereon againstthe housing surrounding a relief passage connecting the second sectionof said oxygen chamber with said second sensing chamber, said secondpressure differential overcoming said second resilient means to allowoxygen under pressure in the second section to flow into said secondsensing chamber and thereby eliminate said third pressure differential.6. The oxygen regulator, as recited in claim 5, wherein said third wallmeans includes: piston means having a passage therethrough forconnecting said first section with the second section of said oxygenchamber; and an adjustable valve associated with said piston means forestablishing said restriction for regulating the flow of oxygen from thefiRst section to the second section.
 7. The oxygen regulator, as recitedin claim 6, wherein said third wall means further includes: a firstdiaphragm fixed to said housing and secured to said piston means forestablishing said second section of the oxygen chamber with saidhousing; and a second diaphragm fixed to said housing and secured tosaid piston for establishing said first section in the oxygen chamber,with said first diaphragm and said housing.
 8. The oxygen regulator, asrecited in claim 7, wherein said piston means inclues: a stem attachedto said piston and extending into said third ambient chamber.
 9. Theoxygen regulator, as recited in claim 8, wherein said third valve meansincludes: a disc having an axial opening through the center thereof witha face on one side thereon; a cylindrical guide attached to said discand adjacent said axial opening, said cylindrical guide surrounding saidstem for aligning said disc on said piston means; a cap attached to saidstem, said cap engaging said disc causing the disc to be correspondinglymoved as the piston means is moved by said third and fourth pressuredifferentials; and a spring located between said piston means and saiddisc for urging said face toward said second inlet port, said springallowing said cylindrical guide to move on said stem to vent saidbreathable fluid from said mixing chamber upon the pressure thereofreaching a predetermined value.
 10. The oxygen regulator, as recited inclaim 9, wherein said control means includes: aneroid means located in asixth chamber, said sixth chamber being in free communication withambient air; a shaft having one end connected to said aneroid means andanother end extending through a bearing wall of said housing; a sleevesurrounding said shaft having a shoulder abutting said another end, saidsleeve having a first face thereon which extends into said first passagegoing to the first sensing chamber and a second face thereon whichextends into said second passage going to the second sensing chamber,said aneroid moving said sleeve through said shaft from a first positionwhere said first face closes said first passage while said second faceunobstructs said second passage through a variable number of positionscorresponding to an increase in altitude to a final position where saidfirst face unobstructs said first passage while said second face closessaid second passage.
 11. The oxygen regulator, as recited in claim 10,wherein said control means further includes: a lever arm connected tosaid shoulder of the sleeve and pivotally retained in the housingadjacent said first ambient chamber; and spring means connected to saidlever arm and said first diaphragm for providing a connection with saidaneroid means to provide automatic pressure breathing above apredetermined altitude.